The tank is overstocked. Fish should have been chosen according to a formula of one gallon per inch at maximize size?
< Not really a hard and fast rule. When the tank is stabilized you need to keep track of the nitrates. Keep them under 25 ppm with water changes. If this cannot be done in between water changes then you need to reduce the bioload and keep fewer fish in the tank.> In that case, I needed a hundred more gallons! I need advice on compatibility; some sites differ. Regarding the black knives – no one but one site said they should be solitary and one other said just to never have two males together. Sexing was suggested by length differences (25cm for female and 30cm for male) and female adult head looks like juvenile head. This was unhelpful because both are 4-5″ juveniles. Brown knives seem to be ok, but all knives I now realize need covered hiding places. I purchased an acrylic tube but that’s not enough for them. Greek themed decorations don’t seem to offer this covering. < The knife fish you have chosen are nocturnal predators that require a dark area to hide in during the day. Without t
